Diagnostic changes as a reason for the increase in papillary thyroid cancer incidence in Geneva, Switzerland

Objective: Several studies have reported upward incidence trends of papillary thyroid cancer. It is unclear whether these trends reflect a real risk increase, by some attributed to iodine supplementation, or an artificial one, due to increased diagnostic activity or changed histological criteria. This study examines if these artificial factors explain the increased papillary thyroid cancer incidence in the Swiss canton of Geneva. Methods: All thyroid carcinomas (n = 436) recorded between 1970 and 1998 at the Geneva Cancer Registry were considered. European age-adjusted incidence trends were estimated using linear regression analysis. For papillary cancers we evaluated diagnostic modalities and way of presentation (in particular microcarcinoma < 1 cm or silent carcinoma). In addition, we reviewed the histological slides of follicular carcinomas. Results: Papillary thyroid cancer incidence increased significantly from 0.7 to 1.8/100,000 for men and from 3.1 to 4.3/100,000 for women between 1970-74 and 1995-98. The proportion of microcarcinomas and silent carcinomas increased from 17% to 24% between 1970-79 and 1990-98. At histological review, follicular cancers were more often reclassified as papillary cancer for cases diagnosed between 1970 and 1979 than for cases diagnosed between 1990 and 1998 (45% vs 25%, p = n.s.). Conclusions: The increasing papillary thyroid cancer incidence seems mainly due to changes in histological diagnostic criteria and, to a lesser extent, to increased diagnostic activity. If confirmed, the results of this study indicate that fears of increasing incidence rates of papillary thyroid cancer should not prevent implementation of adequate programs of iodine supplementation in the many areas where iodine deficiency still prevail

Determinants of genetic counseling uptake and its impact on breast cancer outcome: a population-based study

Genetic counseling and BRCA1/BRCA2 genes testing are routinely offered in a clinical setting. However, no data are available on the proportion of breast cancer patients with a positive family history undergoing genetic counseling. By linking databases of the Oncogenetics and Cancer Prevention Unit at the Geneva University Hospitals and the population-based Geneva Cancer Registry, we evaluated the uptake of genetic counseling among 1709 breast cancer patients with familial risk of breast cancer and the determinants of such a consultation process. We also studied the impact of genetic counseling on contralateral breast cancer occurrence and survival. Overall, 191 (11.2%) breast cancer patients had genetic counseling; this proportion was 25.1% within the high familial risk group. Recent period of diagnosis, early-onset breast cancer, female offspring, high familial risk, tumor size, and chemotherapy treatment were statistically significantly associated with genetic counseling uptake in multivariate analysis. More than 2% of patients had developed contralateral metachronous breast cancer. An increased risk of contralateral breast cancer of borderline significance was found for patients who had genetic counseling versus those who had not (Cox model adjusted hazard ratio 2.2, 95% confidence intervals 1.0-5.2, P=0.063). Stratification by BRCA1/BRCA2 mutation status showed that the occurrence of contralateral breast cancer was 8-fold higher among mutation carriers compared with non-carriers. Age-adjusted overall survival and breast cancer-specific survival were not significantly different between patients who underwent genetic counseling and those who did not. In conclusion, we observed a significant increase in the use of genetic counseling over time and found that breast cancer patients with high familial risk had more often genetic counseling than those with moderate familial risk. A more thorough evaluation of sociodemographic and clinical predictors to attend the cancer genetic unit may help improving the use of genetic counseling services for at-risk individuals at a population level